Kendler K S, Gardner C O, Prescott C A
Department of Psychiatry, Medical College of Virginia of Virginia Commonwealth University, Richmond, USA.
Arch Gen Psychiatry. 1999 Apr;56(4):322-7. doi: 10.1001/archpsyc.56.4.322.
Major depression (MD) is both clinically and etiologically heterogeneous. We attempt to relate clinical and etiologic heterogeneity by determining those features of MD that reflect a high familial liability to depressive illness.
Our sample, 3786 personally interviewed twin pairs from a population-based registry, contained 1765 people with a lifetime history of MD by DSM-III-R criteria, of whom 639 (36.2%) had affected co-twins. We examine, using Cox proportional hazard models, the clinical features of MD in affected twins that predicted the risk for MD in the co-twin. Control variables were zygosity, age at interview, and sex of the twin and co-twin.
The best-fitting model contained 4 significant predictors: number of episodes, duration of longest episode, recurrent thoughts of death or suicide, and level of distress or impairment. These 4 clinical features were similarly predictive of the risk for MD in the co-twins of male and female twins and predicted risk of illness more strongly in monozygotic than in dizygotic twins. Variables that did not uniquely predict risk of MD in the co-twin included age at onset and number of depressive symptoms. For number of episodes, the best-fitting model indicated an inverted U-shaped function with greatest co-twin risk for MD with 7 to 9 lifetime episodes.
The clinical features of MD in epidemiologic samples can be meaningfully related to the familial vulnerability to illness. Familial MD is best characterized by intermediate levels of recurrence, long duration of episodes, high levels of impairment, and recurrent thoughts of death or suicide. These clinical features probably reflect a high genetic liability to depressive illness.
重度抑郁症（MD）在临床和病因方面均具有异质性。我们试图通过确定那些反映出对抑郁症有较高家族易感性的MD特征，来关联临床和病因异质性。
我们的样本来自一个基于人群的登记处，包含3786对接受个人访谈的双胞胎，其中1765人有符合DSM-III-R标准的MD终生病史，其中639人（36.2%）的同卵双胞胎也患有MD。我们使用Cox比例风险模型，研究了患病双胞胎中MD的临床特征，这些特征可预测其同卵双胞胎患MD的风险。控制变量包括双胞胎的合子性、访谈时的年龄以及双胞胎和同卵双胞胎的性别。
拟合度最佳的模型包含4个显著预测因素：发作次数、最长发作持续时间、反复出现的死亡或自杀念头以及痛苦或损害程度。这4个临床特征对男性和女性双胞胎的同卵双胞胎患MD风险的预测作用相似，并且在单卵双胞胎中比在双卵双胞胎中对患病风险的预测更强。不能唯一预测同卵双胞胎患MD风险的变量包括发病年龄和抑郁症状数量。对于发作次数，拟合度最佳的模型显示出倒U形函数，终生发作7至9次时，同卵双胞胎患MD的风险最高。
流行病学样本中MD的临床特征可以与家族性患病易感性有意义地关联起来。家族性MD的最佳特征是复发水平中等、发作持续时间长、损害程度高以及反复出现死亡或自杀念头。这些临床特征可能反映了对抑郁症的高遗传易感性。
